The invention, 3-D Localization of Clustered Microcalcifications using Cranio-Caudal (CC) and Medio-Lateral Oblique (MLO) Views, is a computer-aided 3-D localization method for needle biopsies in positioning breast clustered microcalcifications using Cranio-Caudal and Medio-Lateral Oblique Views. In coordination with a mammographic equipment, a 3-D breast virtual model can be displayed on personal computers or workstations installed with the system of the Invention. The method is of great help for doctors in identification of the spatial locations of clustered microcalcifications in breasts and the accurate determination of the number and coverage of clustered microcalcifications. The frequency of needle localization for biopsy can be considerably decreased, and thus waste of medical resources greatly reduced and efficiency enhanced.
According to the report of Department of Health, Executive Yuan, breast cancer is the second most frequent occurring cancer among women in Taiwan, the morbidity and mortality of which is unfortunately continuously increasing.
At present, mammography is generally recognized as the most effective photographic tool for detecting early breast cancer that reported in 1992 by L. W. Bassett on Radiological Clinics of North America (vol. 30, pp. 93-105). Appearance of clustered microcalcifications is a signal of an impalpable early breast cancer. In 1990, S. A. Feig et al. published in Diagnostic Imaging (vol. 11, pp. 132-138) that 90% of nonpalpable in situ ductal carcinomas and 70% of nonpalpable minimal carcinomas are visible on microcalcifications alone. Diagnosis of microcalcifications of malignant breast cancer was becoming vital. In xe2x80x9cDiagnosis and Differential Diagnosis of Breast Calcificationsxe2x80x9d (pp.91-107) in 1986, M. Lanyi had claimed that, as early as 1960, many researches indicated some features of clustered microcalcifications were important for diagnosing malignant and benign breast cancer. However, according to the report published in Radiology (vol. 137, pp. 1-7) made by R. L. Egan et al. through analysis of a great number of cases, diagnoses of clustered calcifications were not reliable because of co-existence of both malignant and benign features. This makes diagnostic interpretation difficult. In this situation, most radiologists encourage biopsies, in spite of the fact that only 20%-30% of cases are proved to be malignant.
On average clinical diagnosis via mammography, two views will be taken of the same breast: one is the cranio-caudal view (CC View), taken from a xe2x80x9chead to toexe2x80x9d angle, and the other is the medio-lateral oblique view (MLO View), taken from an xe2x80x9cobliquexe2x80x9d angle. Doctors could initially determine the positions of lesions with the help of these two images before needle biopsy. But, when there are two or more clustered microcalcifications existing at the same time, or when clustered microcalcifications appear indistinct, it is not easy to exactly localize the clustered microcalcifications via these two images only. Thus, a needle localization method is adopted. To be brief, this is a method of repeating again and again the cycle of giving needle biopsies, taking mammograms, and calibrating the penetrating position till the exact lesion is detected. And then, a sample section is cut according to the position of the needle tip. Such operations as this have a heavy cost in terms of medical labor and resources to ensure lesion localization; besides, the invasion of needle biopsies and the X-ray of mammography is also painful and distressing for the patient.
Although there were a great many doctors engaged in efficient computer-aided mammographic systems from 1987 to 1996, most of these were diagnostic and analytic tools for microcalcifications in mammography, and provide little help with needle biopsies. [reported by H. P. Chan et al. on Med. Phy. (vol. 14, no. 4, pp. 538-548) in 1987, and by A. P. Dhawan et al. on IEEE Trans. On Medical Imaging (vol. 15, no. 3, pp. 246-259) in 1996.]
Regarding patents on localization of breast cancer lesions and on diagnosis and analysis of clustered microcalcifications. Some of these are for equipment such as: U.S. Pat. No. 5,183,463 which describes an xe2x80x9cApparatus for locating a breast mass,xe2x80x9d which is a cell sampling device for palpable breast tumor and is completely different from the Invention emphasizing an automatic localization and 3-D display. U.S. Pat. No. 51,974,824 describes a xe2x80x9cHelical-tipped lesion localization needle device,xe2x80x9d which is equipped with a spiral thin needle convenient for users to prick into the marked lesions in the breast and thus has nothing to do with the Invention""s localization method. U.S. Pat. No. 5,386,447 describes xe2x80x9cMammographic screening and biopsy apparatus,xe2x80x9d which is a special equipment patients can lie on a platform allowing the breasts to be placed vertically through the corresponding holes in the platform convenient for taking mammograms of a lesion with two different angles. These two images are useful for adjusting the needle positions. Although this equipment adopts the same method of taking mammograms of lesions as the Invention, there is still a great difference between themxe2x80x94it is the users that calibrate the needle positions with reference to the images, no computer-aided 3-D breast virtual model is displayed. U.S. Pat. No. 5,412,706 describes a xe2x80x9cMammogram marking system,xe2x80x9d which is a device used for adding remarks on the mammograms and is irrelevant to the Invention.
The other patents are specialized on methods of treatment, such as: U.S. Pat. No. 4,930,143 which describes a xe2x80x9cMethod and device for mammographic stereotactic punction of pathological lesions in the female breast,xe2x80x9d which consists of a method and equipment for improving needling accuracy. Thus again, without a computer-aided 3-D breast virtual model display, this patent has nothing to do with the Invention. U.S. Pat. No. 5,301,682 describes a xe2x80x9cMethod for locating a breast mass,xe2x80x9d which is an improved drawing device that can draw out tumor organizations and is also irrelevant to the Invention which emphasizes a 3-D breast virtual model display. U.S. Pat. No. 5,409,004 describes a xe2x80x9cLocalization device with radiopaque markings,xe2x80x9d which is a device for directing operations and, with its in-built needle, for cell sampling. It also is clearly quite different from the Invention because of its absence of computer-aided 3-D mammographic display. U.S. Pat. No. 5,426,685 describes the xe2x80x9cStereotactic mammography system imaging,xe2x80x9d which provides a special bed for a patient to lie on and let her breasts hang down, and in such a way as to allow 3-D mammography to be carried out. Like the Invention, this method is used to take 3-D lesions display; the major difference between them is: this method needs special equipment, but the Invention uses only traditional mammographic equipment to take mammograms and a computer to process the mammograms produced. Besides, the Invention uses a 3-D breast virtual model display to show the relative positions of lesions in the breasts. U.S. Pat. No. 5,544,219 describes the xe2x80x9cProcedure for automatic position-finding of points of interest during a mammography examination using stereotactic technique,xe2x80x9d which provides a mammographic procedure for finding the positions of lesions of interest. It is different from the technique of position calibration used in the Invention and offers no 3-D display. U.S. Pat. No. Des. 360,947 describes the xe2x80x9cMammography imaging machine,xe2x80x9d which is a new mammographic device but has nothing to do with lesion localization. U.S. Pat. No. 5,594,769 describes the xe2x80x9cMethod and apparatus for obtaining stereotactic mammographic guided needle breast biopsies,xe2x80x9d which is an additive apparatus to the traditional mammographic device and is used in 3-D calibration of lesions. Like the Invention, it uses the traditional mammographic device; however, the greatest difference between them is that this device does not offer computer-aided 3-D breast and lesions display. Lastly U.S. Pat. No. 5,712,890 describes a xe2x80x9cFull breast digital mammography device,xe2x80x9d which produces a complete mammography of breasts and is irrelevant to the lesions positioning.
The chief purpose of the xe2x80x9c3-D Localization of Clustered Microcalcifications Using Cranio-Caudal(CC) and Medio-Lateral Oblique (MLO) Viewsxe2x80x9d is to describes a computer-aided localization method for needle breast clustered microcalcifications biopsies.
In common clinic mammographic diagnoses, it will be easier to determine the positions of lesions by collaboration of the CC and MLO Views. But in some cases of more than one clustered microcalcifications or of vague clustered microcalcifications, it is not easy to localize the clustered microcalcification(s) using these two images only. Therefore, we have designed a computer-aided system for localizing clustered microcalcificationsxe2x80x94using a computer system to analyze the features of clustered microcalcifications: gradient, energy and local entropy codes. Through multiple grouping calibrations, a 3-D spatial model of breast and lesions are thus established. The Invention is helpful to doctors in re-building the spatial information of clustered microcalcifications in a breast, identifying the exact number of clustered calcifications and the spread of their coverage, reducing the times of needle biopsies, decreasing waste of medical resources and thus enhancing diagnostic efficiency.
Anyone who is familiar with related techniques will clearly understand the purpose and merits of the Invention after reading the full case remarks illustrated by various figures as listed below.